JP2000094673A - Ink jet recording device - Google Patents

Abstract

(57) Abstract: A conductive material for connecting an electrode and a printed circuit board protrudes and comes into contact with a conductive member. SOLUTION: An anisotropic conductive film 26 after connecting a printed board 25 and an individual electrode 21 is located inside an end of the printed board 25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus for protecting a connection between an ink jet head and a printed circuit board.

[0002]

2. Description of the Related Art An ink jet head used in an ink jet recording apparatus used as an image recording apparatus such as a printer, a facsimile, a copying machine, etc. has a nozzle hole for discharging ink droplets and a discharge chamber (pressure chamber, pressure chamber, etc.) communicating with the nozzle hole. Also referred to as a pressure liquid chamber, a liquid chamber, an ink flow path, etc.)
And an energy generating means for generating energy for pressurizing the ink in the discharge chamber, and driving the energy generating means to pressurize the ink in the discharge chamber to discharge ink droplets from the nozzle holes. The ink-on-demand type which discharges ink droplets only when necessary is the mainstream. And ink drops (recording liquid)
Are roughly classified into several types according to the generation method of the phenomena and the control method for controlling the flight direction.

[0003] The first method is disclosed, for example, in US Patent No. 3060.
No. 429. this is,
This is called the Tele type system, and ink droplets are generated by electrostatic attraction, the generated ink droplets are subjected to electric field control according to a recording signal, and the ink droplets are selectively attached to a recording medium to perform recording. Is what you do.

More specifically, an electric field is applied between the nozzle and the accelerating electrode to discharge uniformly charged ink droplets from the nozzles, and the discharged ink droplets can be electrically controlled in accordance with a recording signal. In this case, the ink droplets are caused to fly between the XY deflection electrodes, and ink droplets are selectively deposited on the recording medium by a change in the intensity of the electric field.

The second method is disclosed in, for example, US Pat.
No. 275, U.S. Pat. No. 3,298,030, and the like. This is called the Sweet method, in which ink droplets having a controlled charge amount are generated by a continuous vibration generation method, and the ink droplets having the controlled charge amount fly between deflection electrodes to which a uniform electric field is applied. Thus, recording is performed on the recording medium.

More specifically, a charging electrode, to which a recording signal is applied, is separated by a predetermined distance from an orifice (ejection port) of a nozzle, which is a part of a recording head provided with a piezoelectric vibrating element. The piezo-vibration element is mechanically vibrated by applying an electric signal of a constant frequency to the piezo-vibration element, and ink droplets are ejected from the orifice. At this time, a charge is electrostatically induced in the discharged ink droplet by the charging electrode, and the ink droplet is charged with a charge amount according to the recording signal. The ink droplet whose charge amount is controlled is deflected according to the added charge amount when flying between the deflecting electrodes to which a constant electric field is uniformly applied, and only the ink droplet carrying the recording signal is recorded on the recording medium. Will adhere to the top.

A third method is disclosed in, for example, US Pat.
No. 153 specification. this is,
This is a method called the Hertz method, in which an electric field is applied between the charging electrodes in the form of nozzles, and ink droplets are generated and atomized by a continuous vibration generation method for recording. That is, the intensity of the electric field applied between the nozzle and the charging electrode is modulated in accordance with the recording signal to control the atomization state of the ink droplets, and the image is recorded with the gradation of the recorded image.

The fourth method is disclosed in, for example, US Pat.
No. 120 is disclosed. this is,
It is called the Stemme system, and its principle is fundamentally different from the first to third systems. That is, all of the first to third systems electrically control ink droplets ejected from nozzles during flight, and selectively deposit ink droplets carrying a recording signal on a recording medium. On the other hand, in the Stemme method, ink droplets are ejected and ejected from ejection ports in accordance with a recording signal to perform recording.

In other words, in the Stemme method, an electric recording signal is applied to a piezoelectric vibrating element attached to a recording head having a discharge port for discharging a recording liquid to change the vibration into mechanical vibration of the piezoelectric vibrating element. Ink droplets are ejected and ejected from ejection ports in accordance with mechanical vibration and adhere to a recording medium.

[0010] Each of these four methods has its own features, but at the same time, has disadvantages. First, in the first to third systems, direct energy for generating ink droplets is electric energy, and deflection control of ink droplets is also performed by electric field control. Therefore, the first method is simple in configuration, but requires a high voltage to generate small droplets, and it is difficult to use a multi-nozzle recording head, and is not suitable for high-speed recording.

In the second method, the recording head can be multi-nozzle, and is suitable for high-speed recording. However, the configuration is complicated, and electrical control of ink droplets is advanced and difficult.
Satellite dots easily occur on the recording medium. The third method enables recording with excellent gradation by atomizing ink droplets, but it is difficult to control the atomized state. In addition, there are disadvantages such as fogging of a recorded image and difficulty in multi-nozzle recording head, which is not suitable for high-speed recording.

On the other hand, the fourth method has relatively many advantages. That is, first, the configuration is simple,
Since the recording is performed by discharging the ink droplets from the nozzles on demand, it is not necessary to collect the ink droplets which are not required for image recording, as in the first to third systems. Further, unlike the first and second systems, it is not necessary to use a conductive ink, and the degree of freedom in selecting the material of the ink is large.

However, it is difficult to make the recording head multi-nozzle because it is extremely difficult to reduce the size of the piezoelectric vibrating element having a desired resonance frequency. Further, since the ink droplets are ejected and fly by the mechanical energy of the mechanical vibration of the piezo-vibration element, it is not suitable for high-speed printing in combination with the difficulty of the multi-nozzle described above.

Therefore, as disclosed in, for example, Japanese Patent Application Laid-Open No. 56-9429, the ink in the liquid chamber is heated to generate air bubbles, causing a rise in the pressure of the ink. And Japanese Patent Publication 6
As disclosed in Japanese Patent Application Publication No. 1-59914, by heating a part of the liquid in a liquid passage communicating with a discharge port for discharging a liquid in a predetermined direction to cause film boiling,
There is a method of forming a flying droplet of liquid ejected from an ejection port and attaching the droplet to a recording medium to perform recording.

A recording head of this type is disclosed in Japanese Patent Publication No. 62-5 / 1987.
As described in Japanese Patent No. 9672, a plurality of active elements such as a heating element and a piezoelectric element are fixedly provided at predetermined positions on a substrate as energy generating means for applying energy for ink picking to ink. After (electrodes are appropriately formed), a photosensitive composition layer is formed at a predetermined thickness on the substrate surface by a coating method or the like, and a usual photolithography method is used.
An ink flow path groove for forming an ink flow path such as an orifice section, an action section, an ink supply path section, and an ink discharge path section is formed, and thereafter, an upper lid is joined to manufacture a recording head. .

By using the phototriso technology in this way, it is possible to increase the density, but it is necessary to heat the heating element to a high temperature in the ink, and to instantaneously expand and expand bubbles.
The heating element is easily deteriorated due to the heat stress or the impact due to the disappearance, and the heating element is in direct contact with the ink, so that the degree of freedom of the usable ink is small.

As a technique for solving these problems and realizing high density by using the phototriso technology, as described in JP-A-4-52214, JP-A-3-293141 and the like, A second substrate in which a liquid chamber and a diaphragm forming one wall surface of the liquid chamber are formed by etching on a first substrate (diaphragm substrate) made of a silicon substrate, and an electrode is formed below the first substrate. The substrate (electrode substrate) is placed, the electrodes are opposed to each other with a predetermined gap between the diaphragms, and a voltage is applied between the diaphragms and the electrodes. 2. Description of the Related Art An electrostatic inkjet head that changes the product and ejects ink droplets from nozzles communicating with a liquid chamber is known.

As a configuration for applying a drive waveform to the electrodes (individual electrodes) of the electrostatic ink jet head, for example, as described in Japanese Patent Application Laid-Open No. There is known one in which a plate is connected with an anisotropic conductive film.

[0019]

In an electrostatic ink jet head having a diaphragm substrate provided on an electrode substrate as described above, the electrode substrate is formed larger than the diaphragm substrate for taking out electrodes. An electrode on the electrode substrate is extended outside the diaphragm substrate to form an electrode extraction portion, and the electrode extraction portion is connected to the printed board via the above-described conductive material such as an anisotropic conductive film or solder. become.

In this case, a conductive material such as an anisotropic conductive film or solder protrudes when connecting the printed circuit board and the electrode, and comes into contact with the diaphragm or the adjacent electrode or comes very close to each other. However, in particular, in the case of a so-called side shooter type electrostatic inkjet head in which the displacement direction of the diaphragm coincides with the ink droplet ejection direction, the electrode forming surface for forming the individual electrodes of the electrode substrate is the same as the nozzle surface. In addition, since the electrode forming surface and the nozzle surface are close to each other in accordance with the miniaturization of the head, the connecting portion between the electrode and the printed circuit board is in a state extremely close to the nozzle surface.

On the other hand, in an ink jet recording apparatus, in order to perform reliability maintaining operations such as ink droplet ejection, wiping of a nozzle surface, and suction and discharge of ink in a nozzle,
The ink remaining on the nozzle surface due to the reliability recovery operation intrudes between the diaphragm or the electrode and the conductive material that is very close to the nozzle and causes a leak, which makes it impossible to discharge or malfunctions. Channels may occur and may lack long-term stability and reliability.

The above-mentioned problems are not limited to the electrostatic type ink jet head having the electrodes arranged as opposed to the vibration plate as the actuator means, but, for example, to the ink jet head having the laminated piezoelectric element disposed on the substrate. This also occurs when an electrode extraction portion (electrode pattern) for providing a drive waveform to the electromechanical transducer is provided on the substrate and the electrode extraction portion is connected to the printed circuit board. . However, when the stacked piezoelectric element is used, the nozzle face and the electrode pattern are farther apart than the electrostatic ink jet head, so the former problem is not so remarkable as in the case of the electrostatic ink jet head.

The present invention has been made in view of the above problems, and has as its object to provide an ink jet head recording apparatus which is low in cost and has improved reliability.

[0024]

In order to solve the above-mentioned problems, an ink jet recording apparatus according to the first aspect of the present invention provides a nozzle for discharging ink droplets, a liquid chamber to which the nozzle communicates, and a method for adding ink in the liquid chamber. A pressure generating means for generating a pressure for ejecting ink droplets from said nozzles by pressurizing, said conductive material being applied to an electrode formed on a substrate for applying a voltage for operating said pressure generating means. In the ink-jet recording apparatus in which the printed circuit board is connected via the above, the conductive material is located inside the end of the printed circuit board before the connection.

According to a second aspect of the present invention, there is provided a nozzle for discharging ink droplets, a liquid chamber communicating with the nozzle, and a pressure for pressurizing ink in the liquid chamber to discharge ink droplets from the nozzle. An ink jet recording apparatus comprising: an ink jet head having pressure generating means; and a printed circuit board connected to an electrode formed on a substrate to which a voltage for operating the pressure generating means is applied via a conductive material. The conductive material was located inside the edge of the printed circuit board.

According to a third aspect of the present invention, in the ink jet recording apparatus of the second aspect, the pressure generating means of the ink jet head is disposed so as to face the vibration plate forming the at least one wall surface and the vibration plate. A means for applying pressure between the diaphragm and the electrode to deform the diaphragm by electrostatic force and pressurize the ink in the liquid chamber; and a member forming the diaphragm. Is composed of a conductor or a semiconductor.

According to a fourth aspect of the present invention, there is provided an ink jet recording apparatus, comprising: a nozzle for discharging ink droplets; a liquid chamber to which the nozzle communicates; a vibrating plate forming at least one wall surface of the liquid chamber; And an ink-jet head that discharges ink droplets from the nozzles by deforming the vibration plate by electrostatic force by applying a voltage between the vibration plate and the electrode. In an ink jet recording apparatus in which a printed board is connected to an electrode formed on the board via a conductive material, an insulating partition member is provided between the board forming the diaphragm and an end of the printed board. The configuration was adopted.

According to a fifth aspect of the present invention, in the ink jet recording apparatus of the fourth aspect, the separating means is a projection formed integrally with a substrate on which the electrodes are formed.

[0029]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view of a head portion of an ink jet recording apparatus according to a first embodiment of the present invention, FIG. 2 is a perspective view of an ink jet head of the head portion, and FIG. 3 is an enlarged cross-sectional view taken along line AA of FIG. FIG. 4 is an enlarged cross-sectional view of a main part along the line BB of FIG.

The ink jet head 1 is shown in FIGS.
As shown in FIG.
A liquid chamber substrate 11 provided above the liquid chamber substrate 10, an electrode substrate 12 provided below the diaphragm substrate 10, and a nozzle plate 13 provided above the liquid chamber substrate 11; Are formed to communicate with each other.

The diaphragm substrate 10 has a liquid chamber 16 and a concave portion 17 which forms a bottom portion of the liquid chamber 16 and forms a diaphragm 18 which is a first electrode and serves as a common electrode, and supplies ink to each liquid chamber 16. Not shown common ink chamber, common ink chamber and liquid chamber 1
6, a recessed portion, a groove, and the like, which form a fluid resistance portion (not shown) and the like which are not shown. The diaphragm substrate 10 is made of SU
A desired fine liquid chamber pattern is formed by etching a metal substrate such as an S substrate, a silicon substrate, or the like. A liquid chamber substrate 11 in which a through hole 19 corresponding to the liquid chamber 16 and the like are formed on the vibration plate substrate 10 is joined.

A concave portion 20 is formed in the electrode substrate 12, and a predetermined portion (here, 1 μm) is formed on the diaphragm 18 on the bottom surface of the concave portion 20.
m. ), An individual electrode 21 serving as a second electrode opposed to the gap is formed, and the actuator section for displacing the diaphragm 18 to change the inner volume of the liquid chamber 16 by the individual electrode 21 and the diaphragm 18 is formed. Make up.
SiO ₂ for preventing the individual electrode 21 from being damaged by a short circuit or discharge on the individual electrode 21 of the electrode substrate 12.
The individual electrode 21 is provided with an electrode pad 23 extending outside the diaphragm substrate 10 and connected to a printed circuit board.

The electrode substrate 12 is formed by etching a metal such as SUS, glass, Si, or the like to form a concave portion 20. An electrode material such as Ni, A1, Ti / Pt, or Cu is sputtered into the concave portion 20. A film is formed to a desired thickness by a film forming technique such as CVD or vapor deposition, and then a photoresist is formed and etched, so that the individual electrode 2 is formed only in the recess 20.
1 is formed.

The nozzle plate 13 is formed of a metal plate such as Ni or SUS, glass, resin, or the like, and can be manufactured by a known method such as etching or nickel electroforming. This nozzle plate 13
The nozzles 15 are arranged in two rows in a staggered manner to increase the nozzle density. In response to this, the liquid chamber 16 and the vibration plate 18 are provided on the diaphragm substrate 10 and the liquid chamber substrate 11, respectively. The substrate 13 is provided with the individual electrodes 21 arranged in two rows. Further, a water-repellent film is formed on the nozzle surface (surface in the ejection direction) of the nozzle plate 13 by a known method such as a plating film or a water-repellent agent coating in order to ensure water repellency with the ink.

The vibrating plate substrate 10, the liquid chamber substrate 11,
The electrode substrate 12 and the nozzle plate 13 are joined by a direct joining method such as an adhesive or anodic joining, a eutectic joining method, or the like.

The ink jet head 1 has a diaphragm 1
When a driving voltage is applied between the electrode 8 and the individual electrode 21, the diaphragm 18 is deformed by electrostatic force, and the internal volume (volume) of the liquid chamber 16 changes, whereby an ink droplet is ejected from the nozzle 15. You.

Therefore, as shown in FIG. 3, an external circuit (drive I) is provided on the electrode pad 23 of the individual electrode 21 of the ink jet head 1 in order to apply a drive waveform to the individual electrode 21.
C) and a flexible printed cable (FP
The printed board 25 made of C) is connected via an anisotropic conductive film (or solder or the like) 26 which is a conductive material.

As the printed board 25, a plate-shaped printed board base made of glass epoxy resin, phenol resin or the like, or a film-shaped printed board base made of polyimide resin, PET resin or the like can be used. An electrode lead 28 for applying a voltage to the individual electrode 21 is formed on 27.

As a method of electrically connecting the electrode leads 28 on the printed circuit board 25 and the electrode pads 23 of the individual electrodes 21, for example, a method of thermocompression bonding of solder, a method of thermocompression bonding with an anisotropic conductive adhesive, There are a method of pressing the electrodes together, a method of connecting them by wire bonding, a method of connecting them by bumps, and the like. Among these, solder and anisotropic conductive adhesive, by using a method such as pressure welding, it is possible to connect a plurality of electrodes at once, the connection work is efficient,
Cost reduction can be achieved.

Here, in this ink jet head, the individual electrodes 21 and the printed circuit board 25 are electrically connected via the anisotropic conductive film 26. As is known, the anisotropic conductive film (anisotropic conductive film) 26 is obtained by dispersing conductive particles called filler in a thermoplastic or thermosetting resin, and is provided between electrodes. By applying heat and pressure between the electrodes, the anisotropic conductive film is crushed, the filler comes into contact with both electrodes, and conduction between the electrodes can be obtained.

Here, the connection by the anisotropic conductive film 26 will be described with reference to FIG. First, as shown in FIG.
The anisotropic conductive film 26 is temporarily press-bonded to the electrode lead 28 of FIG. Note that a protective film 26a is attached to the anisotropic conductive film 26. The anisotropic conductive film 26 is
Temporarily press-bonded to the inside from the end face of At this time, the retreat amount a of the anisotropic conductive film 26 from the printed board 25
Although it depends on the film thickness of the anisotropic conductive film 26, it is preferably not less than the film thickness, more preferably 2
More than double.

Then, as shown in FIG. 2B, the protective film 26a of the anisotropic conductive film 26 is removed, and the electrode substrate 1
2 electrode pad part and the electrode lead 28 of the printed circuit board 25
Is performed, and the heated pressure bonding head 29 is pressed against a region larger than the electrode width to perform thermocompression bonding. This allows
As shown in FIG. 3C, the printed board 25 is connected to the electrode pads 23 of the individual electrodes 21 via the anisotropic conductive film 26.

At this time, the anisotropic conductive film 26 spreads in the direction of the edge of the printed circuit board 25, but the anisotropic conductive film 26 is retracted from the edge of the printed circuit board 25 by a retreat amount a in anticipation of the amount of expansion. Therefore, the anisotropic conductive film 26 does not protrude from the edge of the printed circuit board 25 as shown in FIG. Note that the anisotropic conductive film 26 is
When temporarily press-bonding to the first side, it is only necessary to align the printed board 25 so that the anisotropic conductive film 26 is positioned inside the end of the printed board 25 and then heat-press.

As described above, the conductive material is positioned inside the end of the printed circuit board before the connection, so that when the printed circuit board is connected with the conductive material, the conductive material is connected to the end of the printed circuit board. The protrusion of the material can be prevented, and the conductive material does not come into contact with the diaphragm or between the adjacent electrodes, thereby improving reliability.

In particular, as in the ink jet head 1, the direction of ejecting ink droplets is perpendicular to the diaphragm surface.
In the case of a so-called side shooter type ink jet head, the electrode surface is in the same direction as the nozzle surface, and the electrode surface and the nozzle surface are close to each other for downsizing the head. Therefore, the ink enters the connection portion between the individual electrode 21 and the printed circuit board 25 by the operation for maintaining the reliability such as the ink droplet ejection, the wiping of the nozzle surface, and the suction and discharge of the ink in the nozzle 15, and the water-based ink is discharged. In this case, because of the conductivity, the adjacent individual electrode 21 leaks due to the ink that has entered, or the electrode lead 28 of the printed circuit board 25 is electrically connected to the incorrect individual electrode 21, causing a discharge failure or erroneous operation. Discharge occurs. The present invention is particularly effective for such a side shooter type ink jet head.

Further, since the conductive material does not protrude from the front end of the printed circuit board, the printed circuit board can be arranged up to the vicinity of the diaphragm board and the nozzle board, and the contact area with the electrode pads can be increased. Become like As a result, the contact resistance is reduced, the adhesive force is increased, and the electrical and mechanical reliability is improved.

The conductive material is not limited to the anisotropic conductive film, but may be solder or the like. In this case, the solder plating position on the electrode lead surface of the printed circuit board may be kept at a position inside the end of the printed circuit board.

Here, a specific configuration of the ink jet head 1 will be described. In the inkjet head employed here, the width of the ink liquid chamber 6 was 0.2 mm, the depth was 2.0 mm, and the pitch was 0.28 mm. A diaphragm plate 10 having a thickness of 0.2 mm formed by etching a Si substrate to form a diaphragm 18 having a thickness of 10 μm, and a 0.5 μm groove (recess 20, which is a gap) formed on a Pyrex glass substrate are formed with Ni at the bottom. Are formed with a width of 0.2 mm and a pitch of 0.28 mm.
The electrode substrate 12 on which the SiO 2 insulating layer 22 was formed was bonded with an adhesive, and a plate thickness of 150 μm was placed on the diaphragm substrate 10.
The liquid chamber substrate 11 and the nozzle plate 13 having a thickness of 30 μm were sequentially bonded with an adhesive to produce an electrostatic ink jet head. The nozzle pitch of this head is 0.28m
m, the number of nozzles is 64 channels.

Then, an anisotropic conductive film (3370C manufactured by Three Bond Co., Ltd .: trade name) was provisionally pressed to the electrode lead 28 of the FPC (printed circuit board) 25. The temporary pressing was performed at a pressing head temperature of a pressing machine of 150 ° C., a pressing pressure of 30 kg / cm ² , and a pressing time of 1 second. Further, the electrode leads 28 of this FPC (printed circuit board) 25
Was completely press-bonded while being aligned with the electrode pad 23 of the inkjet head. This main bonding was performed at a pressing head temperature of a pressing machine of 150 ° C., a pressing force of 30 kg / cm ² , and a pressing time of 20 seconds.

Thus, the FPC 25 is connected to the individual electrode 21 via the anisotropic conductive film so that a driving voltage can be supplied. Further, ink can be supplied from an ink tank through an ink supply port communicating with the ink liquid chamber 16 of the inkjet head.

This head has a configuration in which the diaphragm size: 200 μm × 2 mm, the array density of the diaphragms: 90 dpi (= nozzle array density), the number of diaphragms: 32 × 2 rows = 64 (number of nozzles).

Next, the recording head chip thus formed is completed as an ink flying recording head unit by, for example, the following method. This ink flying recording head unit comprises a manifold formed with a hollow ink supply chamber connected to an ink supply pipe (ink supply means) as a base material, and a recording head chip is fixed to the top of the manifold. Then, the ink supplied from the ink supply pipe is led to the top of the manifold through the ink supply chamber, and supplied to the common ink chamber of the recording head chip from the ink supply port provided at the end of the recording head chip. Due to the capillarity of the supply channel, it is carried to each energy application. Further, the recording head chip covers the periphery thereof and is pressed and fixed by a frame-shaped holding member.

In this ink-jet head, the ink supplied from the ink supply pipe to the ink supply port passes through the common ink chamber and fills the entire ink supply channel. When a drive voltage is individually applied to the diaphragm, an electrostatic force is generated between the individual electrode and the diaphragm, and the diaphragm is displaced toward the individual electrode. When the power is turned off from this state, the diaphragm tries to return to the original state, and due to the sudden volume change at this time,
The ink flies as droplets from the nozzles.

Therefore, with the diaphragm substrate 10 of the ink jet head being grounded, a drive waveform of drive voltage: 120 V pulse width: 30 μsec continuous drive frequency: 2 kHz (at the time of solid printing) is applied to the individual electrodes 21. When the driving waveform was observed with an oscilloscope, no leakage was observed with the ground or with the adjacent electrode.

On the other hand, when the conductive material is not located inside the end of the printed circuit board before connection as in the present invention, as shown in FIG. The anisotropic conductive film 26 (or a conductive material such as solder) interposed between the portions protrudes due to the pressure at the time of thermocompression bonding, contacts the diaphragm substrate 10 and leaks to the ground, or the adjacent individual electrode 21 Leaks occur between the two.

Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 7 is a cross-sectional view of a main part of a head portion of an ink jet recording apparatus according to a second embodiment of the present invention, and FIG. Note that parts corresponding to those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

This embodiment is an example in which the anisotropic conductive film 26 after connecting the printed board 25 and the individual electrodes 21 is located inside the end of the printed board 25. That is, as shown in FIG.
9, the anisotropic conductive film 26 is temporarily pressure-bonded to the electrode leads 28 of the printed circuit board 25. Note that a protective film 26a is attached to the anisotropic conductive film 26.

Here, the anisotropic conductive film 26 does not need to be positioned inside the end face of the printed circuit board 25 and temporarily press-bonded as in the first embodiment. Therefore, the anisotropic conductive film 26 may be fitted to the edge of the printed circuit board 25, which is easy to align (illustrated in the drawing), or slightly protruded from the edge, but slightly penetrated from the edge. Is also good. This eliminates the need for high-precision alignment at the time of temporary bonding, thereby shortening the working time and improving the yield.

Then, as shown in FIG. 2B, the protective film 26a of the anisotropic conductive film 26 is removed, and the electrode substrate 1
2 electrode pad part and the electrode lead 28 of the printed circuit board 25
Is performed, and the heated pressure bonding head 29 is pressed against a region larger than the electrode width to perform thermocompression bonding.

At this time, the anisotropic conductive film 26 spreads in the direction of the edge of the printed circuit board 25, and in some cases, as shown in FIG.
5, which protrudes from the end of 5
6b is removed, and the anisotropic conductive film 26 is aligned with the end of the printed circuit board 25 as shown in FIG.

As described above, the conductive material is located inside the end of the printed circuit board after connection, so that when the printed circuit board is connected with the conductive material, the conductive material is applied to a member such as a diaphragm. There is no contact, and reliability is improved.

In particular, as in the ink jet head 1, the direction of ejecting ink droplets is perpendicular to the surface of the diaphragm.
In the case of a so-called side shooter type ink jet head, the electrode surface is in the same direction as the nozzle surface, and the electrode surface and the nozzle surface are close to each other for downsizing the head. Therefore, the ink enters the connection portion between the individual electrode 21 and the printed circuit board 25 by the operation for maintaining the reliability such as the ink droplet ejection, the wiping of the nozzle surface, and the suction and discharge of the ink in the nozzle 15, and the water-based ink is discharged. In this case, because of the conductivity, the adjacent individual electrode 21 leaks due to the ink that has entered, or the electrode lead 28 of the printed circuit board 25 is electrically connected to the incorrect individual electrode 21, causing a discharge failure or erroneous operation. Discharge occurs. The present invention is particularly effective for such a side shooter type ink jet head.

Further, since the conductive material does not protrude from the tip of the printed circuit board, the printed circuit board is
It can be arranged to the vicinity of the nozzle substrate, and the contact area with the electrode pad can be increased. As a result, the contact resistance is reduced, the adhesive force is increased, and the electrical and mechanical reliability is improved.

The anisotropic conductive film 2 is used as the conductive material.
It is not limited to 6, and solder or the like can be used.

Also, when the common electrode (diaphragm) is formed by forming a conductive film such as a metal such as boron on the insulating material as the diaphragm substrate 10, even if the common electrode (diaphragm) is exposed, The inconvenience that leakage occurs due to contact between the protruding anisotropic conductive film and the protruding anisotropic conductive film is eliminated, but furthermore, when the diaphragm itself is formed of metal or semiconductor without the need for a common electrode forming step, Although the common electrode is largely exposed at the end of the diaphragm substrate, no leakage occurs even in this case, which is more effective.

Here, a specific configuration of the ink jet head 1 will be described. In the inkjet head employed here, the width of the ink liquid chamber 6 was 0.2 mm, the depth was 2.0 mm, and the pitch was 0.28 mm. A diaphragm plate 10 having a thickness of 0.2 mm formed by etching a Si substrate to form a diaphragm 18 having a thickness of 10 μm, and a 0.5 μm groove (recess 20, which is a gap) formed on a Pyrex glass substrate are formed with Ni at the bottom. Are formed with a width of 0.2 mm and a pitch of 0.28 mm.
The electrode substrate 12 on which the SiO ₂ insulating layer 22 was formed was joined with an adhesive, and a plate thickness of 150 μm was placed on the diaphragm substrate 10.
The liquid chamber substrate 11 and the nozzle plate 13 having a thickness of 30 μm were sequentially bonded with an adhesive to produce an electrostatic ink jet head. The nozzle pitch of this head is 0.28m
m, the number of nozzles is 64 channels.

Then, an anisotropic conductive film (3370C, manufactured by Three Bond Co., Ltd .: trade name) was provisionally pressed onto the electrode lead 28 of the FPC (printed circuit board) 25. When ten printed boards were provisionally pressed, the variation from the end was ± 20 μm. The temporary pressing was performed at a pressing head temperature of a pressing machine of 150 ° C., a pressing pressure of 30 kg / cm ² , and a pressing time of 1 second. Further, the tip of the FPC (printed circuit board) 25 is 50 μm from the end face of the diaphragm board 10.
At the position of m, the electrode leads 28 and the electrode pads 23 were aligned and the main bonding was performed. In this final press bonding, the pressure of the pressing head of the pressing machine is 150 ° C., and the pressing force is 30 kg / c.
m ² , and the crimping time was 20 seconds.

At this time, the FPC 25 of the anisotropic conductive film 26
The amount of protrusion from the edge of the
μm (contact with diaphragm substrate 10). Thereafter, the portion of the anisotropic conductive film 26 protruding from the end of the printed circuit board 25 was removed. Removal of this protruding part
For example, the removal was performed using a method of mechanically removing with a sharp cutter or the like. As a result, all of the manufactured FPCs 25 did not come into contact with the diaphragm substrate 10 and were all usable.

As a result, the FPC 25 can be connected to the individual electrode 21 via the anisotropic conductive film to supply a driving voltage. Further, ink can be supplied from an ink tank through an ink supply port communicating with the ink liquid chamber 16 of the inkjet head.

The head has a configuration in which the diaphragm size: 200 μm × 2 mm, the arrangement density of the diaphragms: 90 dpi (= the arrangement density of the nozzles) The number of diaphragms: 32 × 2 rows = 64 (the number of nozzles).

Next, the recording head chip thus formed is completed as an ink flying recording head unit by, for example, the following method. This ink flying recording head unit comprises a manifold formed with a hollow ink supply chamber connected to an ink supply pipe (ink supply means) as a base material, and a recording head chip is fixed to the top of the manifold. Then, the ink supplied from the ink supply pipe is led to the top of the manifold through the ink supply chamber, and supplied to the common ink chamber of the recording head chip from the ink supply port provided at the end of the recording head chip. Due to the capillarity of the supply channel, it is carried to each energy application. Further, the recording head chip covers the periphery thereof and is pressed and fixed by a frame-shaped holding member.

In this ink-jet head, the ink supplied from the ink supply pipe to the ink supply port passes through the common ink chamber and fills the entire area of the ink supply channel. When a drive voltage is individually applied to the diaphragm, an electrostatic force is generated between the individual electrode and the diaphragm, and the diaphragm is displaced toward the individual electrode. When the power is turned off from this state, the diaphragm tries to return to the original state, and due to the sudden volume change at this time,
The ink flies as droplets from the nozzles.

Therefore, as shown in FIG. 7, the diaphragm plate 10 of the ink jet head is grounded, and the individual electrodes 21 are supplied with a driving voltage of 120 V, a pulse width of 30 μsec, a continuous driving frequency of 2 kHz (at the time of solid printing). When a drive waveform was applied and the drive waveform was observed with an oscilloscope, no leakage with the ground or a leak with the adjacent electrode was observed.

Next, a third embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. FIG. 3 is a cross-sectional view of a main part of a head unit of the ink jet recording apparatus of the embodiment. In this embodiment, a partition member 30 having an insulating property for preventing the anisotropic conductive film 26 from protruding is provided between the diaphragm board 10 and the printed board 25.

For the partition member 30, it is preferable to use ceramics or a resin material which is easy to mold. In addition, the size of the partition member 30 may be small enough that the diaphragm substrate 10 and the printed board 25 are insulated from each other, so that the partition member 30 is not broken during the processing operation. Also, if it is too large, the height will be higher than the nozzle surface, and in the width direction, it is necessary to secure a connection area between the printed circuit board 25 and the electrode, so the electrode substrate will be large, A smaller one is preferred. Therefore, the partition member 3
The width of 0 is 1 mm or less, preferably 0.5 mm or less, and the height is also equal to or less than the nozzle surface.

The method of connecting the printed circuit board 25 in this embodiment is as follows. First, as in the second embodiment, the anisotropic conductive film 26 is temporarily pressure-bonded to the electrode leads 28 of the printed circuit board 25. The diaphragm 10 of the head
The partition member 30 is provided in contact with the end surface of the base member by fixing with an adhesive or the like.

Then, the electrode leads 2 of the printed circuit board 25 to which the individual electrodes 21 of the head and the anisotropic conductive film 26 are temporarily adhered.
After the alignment with No. 8, the main bonding is performed with a bonding head. At this time, the anisotropic conductive film 26 is crushed and protrudes from the end of the printed circuit board 25, but is blocked by the partition member 30 so that the anisotropic conductive film 26 does not contact the diaphragm substrate 10. When the drive waveform is applied via the printed circuit board 25, no leakage occurs with the diaphragm board 25 connected to the ground.

The partition member 30 can be formed integrally with the nozzle cover 31 when a nozzle cover 31 for covering the peripheral edge of the nozzle surface 13a is provided as shown in FIG. 10, for example.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
1 and FIG. FIG. 11 is a cross-sectional view of a main part of a head portion of the ink jet recording apparatus of the embodiment, and FIG. 12 is an explanatory diagram illustrating a process of forming a partition member of the embodiment. In this embodiment, a partition member 32 having an insulating property for preventing the anisotropic conductive film 26 from protruding is provided between the diaphragm substrate 10 and the printed circuit board 25 and formed integrally with the electrode substrate 12. is there.

That is, as shown in FIG. 12A, after the pattern of the electrode 21 is formed on the electrode substrate 12, a dry film resist (DFR) 33 is laminated, exposed and developed, thereby forming the partition member 32. The DFR 33 is removed while leaving a portion that becomes. For example, when the negative type DFR 33 is used, as shown in FIG. 3B, a mask 34 having an opening 34a corresponding to a portion serving as a partition member is formed.
Exposure is performed by using the DFR 33 to harden the portion that will become the partition member, and then spray-developed or dip-developed with a developer, as shown in FIG.
The DFR 33 can be removed while leaving a portion (cured portion).

The partition member 32 integral with the electrode substrate 12
Can also be formed by forming a SiO ₂ layer, etching or the like.

In each of the above embodiments, the present invention has been described with respect to an example in which the present invention is applied to an ink jet recording apparatus equipped with an electrostatic ink jet head. The substrate on which the electrode extraction portion for giving a drive waveform to the actuator section is larger than that using an electrothermal conversion element such as an element or a heating resistor), and the electrode is exposed to the outside and connected to a printed circuit board. The present invention can be applied to any inkjet recording device equipped with an inkjet head.

[0083]

As described above, according to the ink jet recording apparatus of the first aspect, the electrode formed on the substrate to which the voltage for operating the pressure generating means of the ink jet head is applied through the conductive material. In the ink jet recording apparatus to which the printed circuit board is connected, the conductive material is located inside the edge of the printed circuit board before connection, so that the conductive material is bonded to the edge of the printed circuit board during bonding by pressing and heating. It does not protrude and comes into contact with a conductive member such as a diaphragm, thereby preventing ejection failure and erroneous ejection and improving reliability.

According to the second aspect of the present invention, there is provided an ink jet recording apparatus in which a printed circuit board is connected to an electrode formed on a substrate to which a voltage for operating a pressure generating means of an ink jet head is applied via a conductive material. In this case, the conductive material is located inside the edge of the printed circuit board, so that the conductive material does not come into contact with conductive members such as the diaphragm, and ejection failures and erroneous ejections are prevented. The performance is improved.

According to the ink jet recording apparatus of claim 3, in the ink jet recording apparatus of claim 2,
The pressure generating means of the ink jet head has a vibration plate forming at least one wall surface, and an electrode disposed opposite to the vibration plate, and the diaphragm is statically applied by applying a voltage between the vibration plates. This is a means to pressurize the ink in the liquid chamber by deforming with electric power, and the member forming the diaphragm is made of a conductor or a semiconductor, so the diaphragm substrate forming the diaphragm must be formed of a conductive material. The reliability of the electrostatic type ink jet head which must be improved can be improved.

According to the ink jet recording apparatus of the fourth aspect, in the ink jet recording apparatus in which the printed circuit board is connected to the electrodes formed on the substrate of the electrostatic type ink jet head via a conductive material, Since a partition member having an insulating property is provided between the end of the printed board and the conductive material protruding from the end of the printed board, the partition member is prevented from coming into contact with the diaphragm, so that a discharge failure occurs. Erroneous ejection is prevented, and the reliability is improved.

According to a fifth aspect of the present invention, there is provided the ink jet recording apparatus of the fourth aspect, wherein
Since the separating means is configured as a protrusion integrally formed with the substrate on which the electrode is formed, the partition member can be easily formed, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a head section of an ink jet recording apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective view of an inkjet head of the head unit.

FIG. 3 is an enlarged sectional view of a main part along AA of FIG. 1;

FIG. 4 is an enlarged sectional view of a main part along the line BB in FIG. 1;

FIG. 5 is an explanatory diagram illustrating a process of connecting a printed board and an electrode according to the embodiment;

FIG. 6 is an essential part cross-sectional view of a conventional inkjet head used for describing the operation of the embodiment.

FIG. 7 is a sectional view of a main part of a head section of an ink jet recording apparatus according to a second embodiment of the present invention.

FIG. 8 is an explanatory diagram illustrating a process of connecting a printed board and an electrode according to the embodiment.

FIG. 9 is a sectional view of a main part of a head section of an ink jet recording apparatus according to a third embodiment of the present invention.

FIG. 10 is an essential part cross sectional view of a head section showing another example of the embodiment;

FIG. 11 is a cross-sectional view of a main part of a head unit of an inkjet recording apparatus according to a third embodiment of the invention.

FIG. 12 is an explanatory view illustrating a step of forming a partition member in the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ink jet head, 10 ... Diaphragm board, 11 ...
Liquid chamber substrate, 12: electrode substrate, 13: nozzle plate, 1
3a: nozzle surface, 15: nozzle, 21: individual electrode, 23
... electrode pads, 25 ... printed circuit board, 26 ... anisotropic conductive film, 30, 32 ... partition member, 31 ... nozzle cover.

Claims (5)

[Claims] A nozzle for discharging ink droplets, a liquid chamber communicating with the nozzle, and pressure generating means for generating a pressure for discharging ink from the nozzle by pressurizing ink in the liquid chamber. In an ink jet recording apparatus having an ink jet head and connecting a printed circuit board via a conductive material to an electrode formed on a substrate to which a voltage for operating the pressure generating means is applied, the conductive material is connected before the connection. An ink jet recording apparatus, wherein the ink jet recording apparatus is located inside an end of the printed circuit board in a state. 2. A nozzle for discharging ink droplets, a liquid chamber communicating with the nozzle, and pressure generating means for generating a pressure for discharging ink from the nozzle by pressurizing ink in the liquid chamber. In an ink jet recording apparatus having an ink jet head and connecting a printed board via a conductive material to an electrode formed on a board to which a voltage for operating the pressure generating means is applied, the conductive material is the printed board An ink jet recording apparatus, which is located inside an end of the ink jet recording apparatus. 3. The ink jet recording apparatus according to claim 2, wherein the pressure generating means of the ink jet head has a vibration plate forming the at least one wall surface, and an electrode arranged to face the vibration plate, By applying a voltage between the diaphragm and the electrode, the diaphragm is deformed by electrostatic force to press the ink in the liquid chamber, and a member forming the diaphragm is made of a conductor or a semiconductor. An ink jet recording apparatus comprising: 4. A nozzle for discharging ink droplets, a liquid chamber communicating with the nozzle, a vibration plate forming at least one wall surface of the liquid chamber, and an electrode disposed to face the vibration plate, An inkjet head that discharges ink droplets from the nozzles by deforming the vibration plate by electrostatic force by applying a voltage between the vibration plate and an electrode,
In an ink jet recording apparatus in which a printed board is connected to an electrode formed on a substrate of the ink jet head via a conductive material, an insulating partition wall is provided between a substrate forming the diaphragm and an end of the printed board. An ink jet recording apparatus comprising a member. 5. The ink-jet recording apparatus according to claim 4, wherein said separation means is a projection integrally formed with a substrate on which said electrode is formed.